Slide7:

Climate Variability: Global Temperature

How do we know about greenhouse gas history?Climate records from polar ice cores:

The history of Earth climate is available from Antarctic and Greenland ice cores.
Temperatures from oxygen isotope ratios.
Greenhouse gases from air bubbles trapped in the ice cores.
Other measurements validate these records. How do we know about greenhouse gas history? Climate records from polar ice cores

The Water Cycle and Climate:

Terrestrial water cycle
Precipitation
Storm and drought intensity
Snowfall
Runoff
Tropical storms
Global ice
Ice sheets and glaciers / sea ice
Sea level The Water Cycle and Climate As the Earth has warmed,
what has happened to Earth’s water resources ?

Slide11:

Where has the Earth warmed? Hotter Equator

Changes in Precipitation:

Changes in Precipitation Less Rain More Rain

Precipitation Intensity Increases:

Precipitation Intensity Increases More days with precipitation
More frequent and intense precipitation
Precipitation increases are due to the strong events

Snow Cover Reduced:

Snow Cover Reduced As temperatures increase:
Snow cover reduced 1-2 days/yr since early 1970’s
Water storage in snow pack is reduced
More precipitation is rain
Snow onset is later
Melt is earlier

Slide15:

days/yr The Water Cycle and Climate Runoff Changes With a warmer land and atmosphere:
Runoff changes:
More precipitation falls as rain
Winter runoff is increased
Winter starts later &amp; ends earlier
Spring runoff pulse is earlier
Summer runoff is decreased

Polar Ice Sheets:

Antarctica: Melting and Thickening:

Antarctica: Melting and Thickening Thickening
due to increased
precipitation Melting around
the edges

Greenland: Melting:

Greenland: Melting

The Water Cycle and Climate:

Precipitation:
More &amp; Heavier events
Storm intensity
Stronger large scale weather patterns:
More intense heavy precipitation &amp; drought
More intense storms including hurricanes
Snowfall decrease
Later freeze, earlier thaw
More precipitation as rain
Earlier runoff
Melting of ice sheets and glaciers
Sea level rise The Water Cycle and Climate With a hotter Earth, what has happened to water resources?

Ecosystem Impacts:Melting Ice in the Arctic:

Ecosystem Impacts: Melting Ice in the Arctic

Ecosystem Impacts: What does this mean for a farmer?:

Ecosystem Impacts: What does this mean for a farmer? He is concerned about climate change effects:
Getting enough water from the river (snow melt) for irrigation
Getting water in the summer
Reservoir management
Urban encroachment

Slide29:

Climate Forecasting more less People,
Development &amp; Pollution

Slide30:

Climate Change and Societal Decisions

Slide31:

Climate Change and Societal Decisions Society can make choices that will affect our environment Present averaged heating due to greenhouse gases Possible future heating: need to limit the amount of heating

What can we do?Change how we live: reduce energy use emphasize sustainability reduce population growthChange our technology: improve energy use efficiency:

What can we do? Change how we live: reduce energy use emphasize sustainability reduce population growth Change our technology: improve energy use efficiency

Thank you!:

The Water Cycle and Climate Human water use 1900 – 2000 :

The Water Cycle and Climate Human water use 1900 – 2000

Slide35:

The Water Cycle and Climate Human water use: Grain Production

Slide36:

Grain Production

Slide37:

For more information
Books:
Richard Alley: The Two–Mile Time Machine. A very readable climate change book for the lay reader written by a noted Penn State Prof.
Brian Fagen: The Long Summer. A discussion of how the warming at the end of the last ice age fostered the development of human civilization.
Jared Diamond: Collapse. As Diamond says: how societies choose to fail or succeed.
Malcolm Gladwell: The Tipping Point. A discussion of how small factors can sometimes result in large changes.
Web Resources:
Climate science web site: www.realclimate.org
US Global Change Research Program: www.usgcrp.gov
UN Environmental Program: www.unep.org
NASA Earth Sciences: earthsciences.gsfc.nasa.gov
Goddard Hydrospheric &amp; Biospheric Sciences: neptune.gsfc.nasa.gov
NASA Goddard Climate Sciences: www.giss.nasa.gov
Climate change figures: www.grida.no/climate/vital/index.htm
USDA Foreign Agricultural Service: www.fas.usda.gov/grain/circular/2004/05-04/graintoc.htm
Worldwatch: www.worldwatch.org
Climate, Water and Life on Earth Peter H. Hildebrand, Ph.D., NASA Goddard